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Number of wifi clients?

krause

Hi,
a friend in my Moodletreff group found that he can‘t connect more than 15 clients to the MoodleBox 2.5.0. Using the Version 2.4.1 there were no problems with 25 clients.

How can I check my MoodleBox? Where does the MoodleBox save its client data? Is the client data saved in RAM or is it saved on the sd card?

Best regards, Ralf

Nicolas

krause I'm suspecting that this is maybe a hardware issue, because nothing was changed related to Wi-Fi config in version 2.5.0 since 2.4.1 (see the release notes).

The new RPi 3B+ is rather picky with the power supply (see eg here and here): if the power supply is not good enough (or if its cable is too long or with bad quality), some problems can occur, and the limitation of the number of Wi-Fi client is one of them. You can see this if the red LED goes off; the RPi 3B+ becomes unstable. I got several feedbacks that confirm this. Please check with your friend whether he has also changed his RPi model.

Client data is available in this file, on the SC card: /var/lib/misc/dnsmasq.leases.

Ratna

Hi Nicolas
Provided that the power supply is good enough, what is the limiting factor for the number of Wi-Fi clients that can be connected?
I see that the wireless network uses a /24 network. So 253 is the theoretical maximum. Do you have any numbers from experience?

Nicolas

Ratna The limiting factor is the hardware: the Raspberry was not designed as a high-performance wireless access point, and cannot handle too many concurrent Wi-Fi clients, and this is the only real limiting factor (DHCP is not).

I've made some live tests. The max Wi-Fi clients I've had was 29. I expect that a sensible real life max number is around 25 clients, just like classic Wi-Fi home routers.

Ratna

Hi Nicolas

Thanks for the number. I hoped, twice as much could connect, with a performance hit. In my planned application the speed can be very low, as long as the connection is stable. I see, it is not going to work that way.

I must put a wireless mesh in the lab. (Kidding, wireless is not my department.) But this discussion reminded me the off-line capabilities of Moodle Mobile. I will try that - once I get the chance.